Enterotoxigenic E. coli (ETEC) is among the most important agents involved in pediatric diarrhea and the single most frequently encountered cause of illness in visitors to these regions. It is estimated that 16 million people from industrialized nations travel to ETEC-endemic regions annually, and that 30-70% of these travelers contract ETEC-related diarrhea. The overall objective of this work is to facilitate development of passive antibody product for prevention of diarrhea caused by ETEC. Colonization of the human intestine requires specific colonization factor antigens (CFAs). Rational design of an effective treatment requires knowledge of the relative incidence of these antigens isolated from patients traveling to affected areas. ImmuCell, together with our colleagues at the University of Texas School of Public Health propose to: (1) screen clinical isolates obtained from travelers to Mexico over the past seven consecutive years to determine the predominant CFA types associated with travelers diarrhea in this population; (2) identify the important, CFA-bearing strains and test them for stable, high level expression; (3) generate vaccine quality CFA antigen from the four most promising strains; (4) Immunize lactating dairy cows and measure milk-borne anti-CFA antibody by ELISA; and (5) functionally characterize the antibodies produced by hemagglutination inhibition. Upon successful completion of the work described in this SBIR Phase I study, the objective is to follow-up with production of kilogram quantities of bovine anti-CFA Ig for use in SBIR Phase II human clinical trial.